I'm very new to the quest of learning Mandarin and i've been looking around for a suitable language pack to use so please forgive me for my, im sure very basic questions

I've already downloaded Earworms rapid chinese vol.1 for my ipod and have been listening to that to get a feel for the language, however looking at some reviews and some sample material from several software programs ive noticed something strange, its probably my inexperience just making me confused but in my rapid earworms audio track the phrase "Dui bu QI" is presented as meaning sorry, but in an sample from a pimslur audio track its said to mean excuse me, additionally, my earworm track says that "lou tcha" means excuse me, not dui bu Qi so its left me a little confused, when listening to people speak chinese, i cant distinguish between the 4 tones at all, all the words seems to be at the same tone :-/